Work machines such as mining shovels and the like are used for excavation work. These excavating machines have work implements which consist of a boom, a stick and a bucket. The stick and bucket are controlably actuated by a set of cables and gear drives. In the drawing shown in FIG. 1, a mining shovel 102 is shown in which the boom 104 remains in a substantially fixed position with respect to the car body 106, the bucket 108 is fixed to the stick 110, and the stick 110 is movable with respect to the boom 104 in response to hoist cables 112 and a gear drive included in a yoke 114. An operator typically manipulates the work implement to perform a sequence of distinct functions which constitute a complete excavation work cycle.
Prior art monitoring and control systems for linkage type machines require multiple sensors to determine the orientation and configuration of the implement linkage or bucket. Linkage sensors such as yo-yo devices and rotary sensors mounted on linkage members moving relative to each other, in general, have not proved to have long life. Also, if not only linkage orientation and configuration with respect to the work machine is required but also position and orientation of the work machine itself within the work site, then separate sensors and systems are required to provide the additional information.
For purposes of understanding the invention, it is important to understand the following typical characteristics of large mining shovels 102: a) The end of the stick 110 furthest away from the bucket 108 does not pass through the boom 104; b) By moving the stick 110 in or out fully, it is easy to position the linkage so there is a known distance between the end of the stick 110 and the center of rotation of the stick yoke 114; and c) The shovel undercarriage 116 will not move when the operator is digging since the same power supply cannot be used for travel and digging simultaneously.
In mining operations, the current practice of delineating ore from waste material or geographic boundaries such as between adjacent properties is by use of flags, stakes, or paint stripes on the material to provide a visual reference to the operator. This practice is less than ideal because flags, stakes, and paint stripes can all be moved or destroyed during normal mining operations plus they may be difficult to see at night.
Ramifications of an operator not following the flagged or staked setup plan can include sending waste material instead of ore to processing, sending ore to be disposed instead of waste material, and/or incorrectly identifying the property from which a load of ore was obtained.
The present invention is directed to overcoming one or more of the problems set forth above.